Anatomy
1 questionsAttachment of the vitreous is strongest at?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 31: Attachment of the vitreous is strongest at?
- A. Foveal region
- B. Back of lens
- C. Across ora serrata (Correct Answer)
- D. Margin of optic disc
Explanation: ***Across ora serrata*** - The **vitreous base** is a 3-4 mm wide circumferential band extending approximately 2 mm anterior and 2 mm posterior to the **ora serrata**, where the vitreous firmly adheres to the **non-pigmented ciliary epithelium** and the **peripheral retina**. - This strong adhesion makes the **vitreous base** the primary point of vitreous attachment, often remaining attached even during significant vitreous detachments. *Foveal region* - While there is some attachment, the vitreous is typically **less firmly adherent** to the foveal region compared to the vitreous base. - Vitreous detachment from the fovea is a common event, rarely leading to significant tearing or strong adherence. *Back of lens* - The vitreous has a weak attachment to the posterior capsule of the lens, known as the **Wieger's ligament** or **hyaloideocapsular ligament**. - This attachment typically **loses strength with age** and is not the strongest overall point of attachment. *Margin of optic disc* - The vitreous attaches to the margin of the optic disc, forming a circular adhesion called the **peripapillary ring**. - This attachment is **less strong** than the vitreous base and is often the first region from which the vitreous detaches during a **posterior vitreous detachment (PVD)**.
Biochemistry
1 questionsNumber of ATP molecules formed per turn of the citric acid cycle is
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 31: Number of ATP molecules formed per turn of the citric acid cycle is
- A. 5
- B. 7
- C. 15
- D. 10 (Correct Answer)
Explanation: ***10*** - Each turn of the citric acid cycle directly produces **1 GTP** molecule (which is equivalent to 1 ATP). - Additionally, it generates **3 NADH** and **1 FADH2**, which upon oxidative phosphorylation yield approximately **2.5 ATP per NADH** and **1.5 ATP per FADH2**. - Total calculation: (3 × 2.5) + (1 × 1.5) + 1 (from GTP) = 7.5 + 1.5 + 1 = **10 ATP equivalents** per turn. *5* - This number is **too low** and does not account for the significant energy yield from the **NADH** and **FADH2** molecules produced during the cycle. - It likely only considers a partial or incorrect calculation of the ATP equivalents generated. *7* - This value is **insufficient** as it underestimates the total ATP generated when considering the contributions from both **direct substrate-level phosphorylation (GTP)** and the **electron transport chain**. - It may arise from an incomplete understanding of the ATP yield from NADH and FADH2. *15* - This number is **too high** for the ATP equivalents produced per turn of the citric acid cycle. - Such a value would imply a higher energy yield from the electron carriers or direct ATP production than is biologically accurate.
Dermatology
1 questionsTinea cruris is caused by which of the following fungi?
NEET-PG 2013 - Dermatology NEET-PG Practice Questions and MCQs
Question 31: Tinea cruris is caused by which of the following fungi?
- A. Epidermophyton (Correct Answer)
- B. Trichosporon
- C. Microsporum
- D. Candida
Explanation: ***Epidermophyton*** - **_Epidermophyton floccosum_** is one of the common dermatophytes responsible for causing **tinea cruris** (jock itch) and tinea pedis (athlete's foot). - **Note:** Tinea cruris can be caused by multiple dermatophytes including **_Trichophyton rubrum_** (most common), **_T. mentagrophytes_**, and **_E. floccosum_**. Among the options listed, Epidermophyton is the only dermatophyte that commonly causes tinea cruris. - Microscopic examination of skin scrapings shows **septate hyphae**, and it typically invades the stratum corneum but **not hair or nails**. *Trichosporon* - **_Trichosporon_** species cause **white piedra** (a fungal infection of the hair shaft) and can cause systemic infections in immunocompromised individuals. - It is **not a dermatophyte** and does not cause tinea cruris. *Microsporum* - **_Microsporum_** species are primarily associated with **tinea capitis** (ringworm of the scalp) and **tinea corporis** (ringworm of the body). - While Microsporum can occasionally involve skin in the groin region, it is **rarely implicated in classic tinea cruris** and is not considered a typical causative agent compared to Trichophyton or Epidermophyton species. *Candida* - **_Candida_** species (e.g., **_Candida albicans_**) cause candidiasis, which commonly presents as **intertrigo** in skin folds, oral thrush, or vaginal yeast infections. - While it can occur in the groin area (**candidal intertrigo**), it is **not a dermatophyte** and is distinctly different from tinea cruris, often presenting with **satellite lesions** and an intensely erythematous, macerated rash.
Forensic Medicine
1 questionsIn forensic pathology, what term describes neck compression injuries caused by forearm pressure?
NEET-PG 2013 - Forensic Medicine NEET-PG Practice Questions and MCQs
Question 31: In forensic pathology, what term describes neck compression injuries caused by forearm pressure?
- A. Garrotting with a stick
- B. Strangulation with rope
- C. Mugging (Correct Answer)
- D. Manual strangulation with hands
Explanation: ***Mugging*** - This is the **standard forensic pathology term** for neck compression injuries caused by **forearm or arm pressure**, typically applied in a "chokehold" or "arm-hold" position. - Also known as **"bansdola"** in Indian forensic literature, this mechanism involves **circumferential or lateral neck compression** by the forearm/arm, often seen in assault or robbery scenarios. - The injury pattern shows **broad, diffuse bruising** without the linear marks of ligature or discrete fingerprint marks of manual strangulation. - Distinguished by the **absence of a ligature mark** and the presence of **deep soft tissue hemorrhages** in the neck structures. *Garrotting with a stick* - This involves **ligature strangulation** where a **ligature is tightened using a stick** or similar implement as a tourniquet. - The injuries show **specific patterned marks** consistent with the ligature and the **twisting mechanism**. - This differs from mugging, which uses direct arm/forearm pressure without any ligature. *Strangulation with rope* - This refers to **ligature strangulation** using a **rope**, resulting in a **distinct linear mark** consistent with the rope's texture and diameter. - The ligature mark is typically **oblique, ascending** in hanging or **horizontal/variable** in strangulation. - The mechanism involves external compression by a **specific ligature object**, not the human forearm. *Manual strangulation with hands* - This involves **direct neck compression** by the **hands, fingers, or thumbs** of an assailant. - Injuries typically include **fingernail abrasions**, **fingertip bruises**, and **crescent-shaped marks** corresponding to individual digits. - These discrete marks are distinct from the **broad pressure pattern** seen in mugging with forearm compression.
Microbiology
1 questionsThe culture medium used for Entamoeba histolytica is
NEET-PG 2013 - Microbiology NEET-PG Practice Questions and MCQs
Question 31: The culture medium used for Entamoeba histolytica is
- A. Robinson's medium
- B. CLED medium
- C. Blood agar
- D. TYI-S-33 medium (Correct Answer)
Explanation: ***TYI-S-33 medium*** - **TYI-S-33 (Trypticase-Yeast extract-Iron-Serum) medium** is the most commonly used axenic culture medium for *Entamoeba histolytica*, meaning it supports the growth of the amoeba in the absence of other microorganisms. - This medium provides the necessary nutrients, including **trypticase**, **yeast extract**, **iron**, and **serum**, for the proliferation and maintenance of *E. histolytica* cultures in vitro. - It is the gold standard for axenic cultivation in research and diagnostic laboratories. *Robinson's medium* - **Robinson's medium** is a diphasic medium, meaning it has both solid and liquid phases, and is used for culturing *Entamoeba histolytica* but it is a **xenic** culture medium, meaning it requires the presence of other microorganisms (bacterial flora). - This medium was historically important but is less commonly used for routine culture and has been largely replaced by axenic media like TYI-S-33 for research and diagnostic purposes. *CLED medium* - The **Cystine-Lactose-Electrolyte-Deficient (CLED) medium** is a differential culture medium primarily used for the isolation and enumeration of urinary pathogens. - It is designed to prevent **swarming of Proteus species** and to differentiate lactose fermenters from non-fermenters, but it is not suitable for growing *Entamoeba histolytica*. *Blood agar* - **Blood agar** is a general-purpose enriched agar medium used for the isolation and cultivation of a wide variety of fastidious and non-fastidious bacteria. - It is particularly useful for demonstrating **hemolytic reactions** of bacteria, which are important for bacterial identification, but it does not support the growth of parasitic protozoa like *Entamoeba histolytica*.
Orthopaedics
1 questionsTrue about proximal fragment in subtrochanteric fracture is?
NEET-PG 2013 - Orthopaedics NEET-PG Practice Questions and MCQs
Question 31: True about proximal fragment in subtrochanteric fracture is?
- A. Flexion
- B. Abduction
- C. External rotation
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - In a subtrochanteric fracture, the **proximal fragment** is under the influence of several strong muscle groups, leading to a characteristic displacement. - The **iliopsoas muscle** causes **flexion**, the **gluteus medius and minimus** cause **abduction**, and the **short external rotators** cause **external rotation**. *Flexion* - The powerful **iliopsoas muscle** inserts on the lesser trochanter and acts to flex the hip. - This muscle pulls the proximal fragment anteriorly and superiorly, resulting in a **flexion deformity**. *Abduction* - The **gluteus medius and minimus muscles** attach to the greater trochanter and exert a strong abducting force. - This action pulls the proximal fragment away from the midline, causing **abduction**. *External rotation* - The **short external rotators** (e.g., piriformis, obturators, gemelli) insert around the greater trochanter. - These muscles collectively cause the proximal fragment to rotate outwards, resulting in **external rotation**.
Pathology
2 questionsWhich of the following is not a myeloproliferative disorder?
Which immunohistochemical marker is primarily associated with glomus tumors?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 31: Which of the following is not a myeloproliferative disorder?
- A. Acute myeloid leukemia (Correct Answer)
- B. Chronic myeloid leukemia
- C. Essential thrombocytosis
- D. Polycythemia vera
Explanation: ***Acute myeloid leukemia*** - *Acute myeloid leukemia (AML)* is a **myeloid neoplasm** characterized by the rapid proliferation of myeloid cells and is classified as an acute leukemia, not a myeloproliferative disorder. - It involves **highly abnormal cells** that impede normal blood cell production, contrasting with chronic myeloproliferative disorders which have a more gradual progression. *Essential thrombocytosis* - This is a true **myeloproliferative disorder** characterized by an **increase in platelet count** and is due to the increased production of megakaryocytes in the bone marrow [1]. - Patients can present with thrombotic or hemorrhagic complications, supporting its classification as a myeloproliferative neoplasm. *Chronic myeloid leukemia* - Chronic myeloid leukemia (CML) is another type of **myeloproliferative disorder**, arising from a genetic mutation leading to excessive production of myeloid cells. - It is associated with the **Philadelphia chromosome** and typically presents in a chronic phase with variable leukocytosis. *Polycythemia vera* - Polycythemia vera is a **myeloproliferative neoplasm** characterized by hyperproduction of red blood cells, often accompanied by leukocytosis and thrombocytosis [1]. - It is associated with mutations in the **JAK2 gene**, leading to increased erythropoiesis and elevation of hemoglobin levels, confirming its classification [1]. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615.
Question 32: Which immunohistochemical marker is primarily associated with glomus tumors?
- A. Cytokeratin
- B. S-100
- C. CD-57
- D. CD-34 (Correct Answer)
Explanation: ***CD-34*** (Marked answer, but controversial) - **IMPORTANT NOTE:** This association is **contested** in modern pathology literature. - Glomus tumors are derived from modified smooth muscle cells of the glomus body and typically show **smooth muscle actin (SMA)** and **vimentin positivity**. - **CD34** is an endothelial marker; while glomus tumors have prominent vascularity, the **neoplastic glomus cells themselves** are generally **CD34-negative**. - The correct positive markers are **SMA, vimentin, and caldesmon** - none of which are options here. - Among the given options, CD-34 may show positivity in the **vascular endothelium** within the tumor, but this does not represent the tumor cells. *CD-57* - **CD57** (HNK-1) is associated with neural differentiation, particularly in peripheral nerve sheath tumors like **schwannoma** or **neurofibroma**. - Glomus tumors lack neural differentiation and are **CD57-negative**. *Cytokeratin* - **Cytokeratin** is a marker for epithelial cells and carcinomas. - Glomus tumors are mesenchymal smooth muscle tumors and are **cytokeratin-negative**. *S-100* - **S-100** protein marks neural crest-derived cells, melanomas, and schwannomas. - Glomus tumors originate from modified smooth muscle cells, not neural crest, and are typically **S-100-negative** (though rare cases may show focal weak positivity).
Psychiatry
2 questionsDoppelganger is a term used to describe which medical phenomenon?
What deficiency may contribute to relapse in a patient who has experienced remission with selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs)?
NEET-PG 2013 - Psychiatry NEET-PG Practice Questions and MCQs
Question 31: Doppelganger is a term used to describe which medical phenomenon?
- A. Shadow following person
- B. Feeling of double of oneself (Correct Answer)
- C. Identification of stranger as familiar
- D. None of the options
Explanation: ***Feeling of double of oneself*** - **Doppelganger** (also called **autoscopy** or **heautoscopy**) refers to the experience of seeing or sensing one's own double or duplicate - This is the **correct definition** of the term doppelganger in medical terminology - Associated with **neurological conditions** (temporal lobe epilepsy, brain lesions, migraine) and **psychiatric conditions** (schizophrenia, dissociative states) - The person perceives their duplicate as a separate entity, which may appear visually or be sensed as a presence *Shadow following person* - This is not a recognized medical or psychiatric phenomenon - Does not describe the autoscopic experience of seeing one's own double - Not related to the definition of doppelganger *Identification of stranger as familiar* - This more closely describes **Fregoli delusion**, where a person believes that different people are actually a single person in disguise - Could also relate to other delusional misidentification syndromes - **Not doppelganger**, which specifically involves seeing one's own double, not misidentifying others - Note: **Capgras syndrome** is the opposite—believing a familiar person has been replaced by an imposter *None of the options* - Incorrect because "Feeling of double of oneself" accurately describes the doppelganger phenomenon
Question 32: What deficiency may contribute to relapse in a patient who has experienced remission with selective serotonin reuptake inhibitors (SSRIs) or tricyclic antidepressants (TCAs)?
- A. Pyridoxine
- B. Cobalamin
- C. Ascorbate
- D. Folate (Correct Answer)
Explanation: ***Folate*** - **Folate (vitamin B9) deficiency** is strongly linked to depression and is a well-established cause of relapse in patients treated with antidepressants. - Folate plays a crucial role in the **one-carbon metabolism pathway**, which is essential for the synthesis of monoamine neurotransmitters including **serotonin, norepinephrine, and dopamine**. - Studies show that **low folate levels** are associated with poor response to SSRIs and TCAs, and folate supplementation can improve antidepressant efficacy. - Approximately **30% of depressed patients** have folate deficiency, making it a clinically significant factor in treatment resistance and relapse. *Cobalamin* - **Cobalamin (vitamin B12)** deficiency can cause neuropsychiatric symptoms including depression and cognitive impairment. - While B12 is important for myelin formation and neurotransmitter synthesis, it is less specifically implicated in antidepressant relapse compared to folate. - B12 deficiency more commonly presents with **cognitive and neurological symptoms** rather than pure mood symptoms. *Pyridoxine* - **Pyridoxine (vitamin B6)** is a cofactor in neurotransmitter synthesis, including serotonin and dopamine. - While B6 deficiency can contribute to mood disturbances, it is not commonly implicated as a primary cause of relapse in antidepressant-treated depression. *Ascorbate* - **Ascorbate (vitamin C)** is an antioxidant with some role in neurotransmitter metabolism. - Severe vitamin C deficiency (scurvy) can have psychiatric manifestations, but it is not typically associated with relapse in patients treated with SSRIs or TCAs.